Motor zero crossing point detection circuit and chip
By using one-way control modules and voltage divider modules in brushless DC motor drives, the resistance structure is simplified, and the problem of high-precision resistance occupies large and current extraction loads is solved, and the silicon wafer area and lower cost are achieved, thus improving the detection sensitivity.
Patent Information
- Application Number
- CN202420852121.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-23
- Publication Date
- 2024-12-31
- Estimated Expiration
- 2034-04-23
AI Technical Summary
In brushless DC motor drive, the prior art requires a large number of high-precision resistors to achieve zero-crossing point detection, resulting in large area occupancy and high cost, and a current extraction load effect, affecting detection sensitivity.
Using one-way control module and voltage divider module, diodes and transistors replace part of high-precision resistors, simplify the voltage divider structure, reduce the number of resistors, realize virtual center point detection, avoid current extraction of suspended phase windings, reduce circuit complexity and calibration cost.
It reduces the silicon wafer area and calibration cost, improves detection sensitivity, avoids the load effect of current extraction, and reduces the performance requirements of the detection module.
Smart Images
Figure CN222280788U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of integrated circuits, and in particular relates to a motor zero-crossing detection circuit and a chip. Background Art
[0002] When driving a brushless DC motor (BLDC), a six-step commutation method is usually used to determine the order in which the motor windings are energized. In order to achieve high efficiency, low torque ripple, and high-speed operation, the motor drive system usually needs to detect the position of the rotor to determine the timing of commutation.
[0003] Specifically, the most commonly used three-phase winding connection of the brushless DC motor is as follows Figure 1 As shown. When the motor is working, the first end of one phase winding (e.g., U phase) among the three-phase windings U, V, and W is connected to the positive power supply (through a power switch, such as MOSFET), and the first end of a phase winding (e.g., V phase) is connected to the negative power supply. The first end of the last phase winding (e.g., W phase) is left hanging, and the specific selection method is determined by the six-step commutation method.
[0004] Taking the above working moment as an example, at this time, the U and V phase windings of the motor are energized and working, and the W phase winding is suspended. The suspended W phase winding interacts with the magnetic field generated by the motor magnet, generating a back electromotive force that changes with the motor speed and rotor position. By detecting the back electromotive force zero crossing event on the W phase winding, the system can detect the position of the motor rotor.
[0005] However, for cost saving and the number of wires, the common center point of the three-phase windings (i.e., the node formed by connecting the second ends of the U, V, and W three-phase windings) is usually not brought out, making it impossible to directly measure the voltage on the W-phase winding. In this case, a "virtual center point" needs to be created for zero-crossing comparison.
[0006] The virtual center point (Zero cross ref) voltage generation circuit used in the prior art for zero crossing detection is as follows: Figure 2 As shown. Specifically, the operation of this circuit is based on the following assumptions: 1. The windings and magnetic field of the motor are symmetrical; 2. No current flows through the W-phase winding. At this time, the voltage drops on the U- and V-phase windings due to back electromotive force, DC resistance, and inductance are exactly the same, so the average value of the line voltage between the U- and V-phase windings is the center point voltage. At the same time, although the back electromotive force on the W-phase winding will inject current into the resistor network and affect the voltage at the virtual center point, we are only concerned about the back electromotive force zero-crossing event. At this moment, the back electromotive force of the W-phase winding is 0, and there is no current injection.
[0007] When the circuit is integrated into a silicon chip (in an integrated circuit), three high-precision resistors R with equal or very close resistance values need to be manufactured on the silicon chip. This will take up a large amount of silicon chip area during the integrated circuit manufacturing process. At the same time, the resistors on the silicon chip have a large manufacturing tolerance, so a calibration Trim operation is required to match the resistance values of the three resistors R, further increasing the cost of the system.
[0008] The information disclosed in this background technology section is only intended to increase the understanding of the overall background of the present invention, and should not be regarded as acknowledging or suggesting in any form that the information constitutes the prior art already known to a person skilled in the art. Utility Model Content
[0009] The utility model aims to provide a motor zero-crossing detection circuit, which can reduce the number of resistors required and reduce the size of silicon chips and calibration costs.
[0010] In order to achieve the above-mentioned object, a specific embodiment of the utility model provides a motor zero-crossing detection circuit, including: a unidirectional control module, a voltage dividing module and a detection module, wherein the first end of the voltage dividing module and the second end of the voltage dividing module are connected to the first end of the U-phase winding, the first end of the V-phase winding and the first end of the W-phase winding of the motor through the unidirectional control module, and the detection module is connected to the voltage dividing module, the first end of the U-phase winding, the first end of the V-phase winding and the first end of the W-phase winding;
[0011] The unidirectional control module is used to control the first ends of two phase windings among the first end of the U phase winding, the first end of the V phase winding and the first end of the W phase winding to form a path between the voltage dividing module and the first end of the U phase winding, the first end of the V phase winding and the first end of the W phase winding;
[0012] The voltage dividing module is used to divide the voltage generated between the first end of the voltage dividing module and the second end of the voltage dividing module to generate a voltage to be measured;
[0013] The detection module is used to compare the voltage to be measured with the voltage of the first end of another phase winding that does not form a path with the voltage dividing module and generate a judgment signal for judging the position of the winding.
[0014] In one or more embodiments of the present utility model, the unidirectional control module includes a first unidirectional control unit and a second unidirectional control unit, the first unidirectional control unit is connected to the first end of the voltage divider module and the first end of the U-phase winding, the first end of the V-phase winding and the first end of the W-phase winding, the first unidirectional control unit is used to control the current to flow from the first end of the U-phase winding, the first end of the V-phase winding or the first end of the W-phase winding to the first end of the voltage divider module, the second unidirectional control unit is connected to the second end of the voltage divider module and the first end of the U-phase winding, the first end of the V-phase winding and the first end of the W-phase winding, the first unidirectional control unit is used to control the current to flow from the second end of the voltage divider module to the first end of the U-phase winding, the first end of the V-phase winding or the first end of the W-phase winding.
[0015] In one or more embodiments of the present utility model, the first unidirectional control unit includes at least three first unidirectional conductive units, and the first end of the U-phase winding, the first end of the V-phase winding and the first end of the W-phase winding are respectively connected to the first end of the voltage divider module through the corresponding first unidirectional conductive units.
[0016] In one or more embodiments of the present utility model, the first unidirectional conductive unit includes a first diode or a first transistor, the anode of the first diode is connected to the first end of the corresponding single-phase winding, the cathode of the first diode is connected to the first end of the voltage divider module, the first end of the first transistor is connected to the control end and to the first end of the corresponding single-phase winding, and the second end of the first transistor is connected to the first end of the voltage divider module.
[0017] In one or more embodiments of the present utility model, the second unidirectional control unit includes at least three second unidirectional conductive units, and the first end of the U-phase winding, the first end of the V-phase winding and the first end of the W-phase winding are respectively connected to the second end of the voltage divider module through corresponding second unidirectional conductive units.
[0018] In one or more embodiments of the present utility model, the second unidirectional conductive unit includes a second diode or a second transistor, the anode of the second diode is connected to the second end of the voltage divider module, the cathode of the second diode is connected to the first end of the corresponding single-phase winding, the first end of the second transistor is connected to the control end and to the second end of the voltage divider module, and the second end of the second transistor is connected to the first end of the corresponding single-phase winding.
[0019] In one or more embodiments of the present utility model, the voltage divider module includes a first voltage divider unit and a second voltage divider unit, the first end of the first voltage divider unit and the second end of the second voltage divider unit are connected to the unidirectional control module, and the second end of the first voltage divider unit and the first end of the second voltage divider unit are connected to the detection module.
[0020] In one or more embodiments of the present invention, the first voltage dividing unit includes a first resistance unit, and / or the second voltage dividing unit includes a second resistance unit.
[0021] In one or more embodiments of the present utility model, the detection module includes a first comparator, a second comparator and a third comparator, the first end of the first comparator is connected to the first end of the U-phase winding, the first end of the second comparator is connected to the first end of the V-phase winding, the first end of the third comparator is connected to the first end of the W-phase winding, and the second end of the first comparator, the second end of the second comparator and the second end of the third comparator are connected to the voltage divider module.
[0022] The utility model also discloses a chip, comprising the motor zero-crossing point detection circuit.
[0023] Compared with the prior art, the motor zero-crossing detection circuit of the utility model simplifies the structure of the voltage divider module by setting a unidirectional control module, that is, reduces the number of high-precision resistors required in the voltage divider module, thereby reducing the area of the voltage divider module, further reducing the area of the silicon wafer and the calibration cost, and when a phase winding is suspended as a back electromotive force sensor, the zero-crossing detection circuit will not draw current from the phase winding, there is no load effect, the system sensitivity is high, and the performance requirements of the detection module are reduced. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the utility model, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.
[0025] Figure 1 The diagram is a three-phase winding connection diagram of a brushless DC motor in the prior art.
[0026] Figure 2 The present invention is a circuit schematic diagram of a zero-crossing detection circuit of a three-phase winding of a brushless DC motor in the prior art.
[0027] Figure 3 This is a circuit schematic diagram of a motor zero-crossing detection circuit according to Embodiment 1 of the present utility model. DETAILED DESCRIPTION
[0028] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.
[0029] The words "coupled" or "connected" or "connected" in the specification include both direct connection and indirect connection. Indirect connection is a connection through an intermediate medium, such as a connection through an electrically conductive medium, which may have parasitic inductance or parasitic capacitance; indirect connection may also include connection through other active or passive devices on the basis of achieving the same or similar functional purpose, such as connection through circuits or components such as switches and follower circuits. In addition, in the utility model, words such as "first" and "second" are mainly used to distinguish one technical feature from another technical feature, and do not necessarily require or imply that there is a certain actual relationship, quantity or order between these technical features.
[0030] like Figure 3 As shown, a motor zero-crossing detection circuit in an embodiment of the utility model includes: a unidirectional control module, a voltage dividing module 20 and a detection module 30.
[0031] The first end of the voltage divider module 20 and the second end of the voltage divider module 20 are connected to the first end of the U-phase winding, the first end of the V-phase winding and the first end of the W-phase winding of the motor through the unidirectional control module, the detection module 30 is connected to the voltage divider module 20, the first end of the U-phase winding, the first end of the V-phase winding and the first end of the W-phase winding, and the second end of the U-phase winding, the second end of the V-phase winding and the second end of the W-phase winding are connected to form a center point O.
[0032] Among them, the unidirectional control module is used to control the first end of the U-phase winding, the first end of the V-phase winding and the first end of the W-phase winding to form a path between the first end of the U-phase winding, the first end of the V-phase winding and the first end of the W-phase winding and the voltage dividing module 20.
[0033] like Figure 3As shown, the unidirectional control module includes a first unidirectional control unit 11 and a second unidirectional control unit 12. The first unidirectional control unit 11 is connected to the first end of the voltage divider module 20 and the first end of the U-phase winding, the first end of the V-phase winding and the first end of the W-phase winding, and the first unidirectional control unit 11 is used to control the current to flow from the first end of the U-phase winding, the first end of the V-phase winding or the first end of the W-phase winding to the first end of the voltage divider module 20. The second unidirectional control unit 12 is connected to the second end of the voltage divider module 20 and the first end of the U-phase winding, the first end of the V-phase winding and the first end of the W-phase winding, and the first unidirectional control unit 11 is used to control the current to flow from the second end of the voltage divider module 20 to the first end of the U-phase winding, the first end of the V-phase winding or the first end of the W-phase winding.
[0034] The first unidirectional control unit 11 includes at least three first unidirectional conductive units, and the first end of the U-phase winding, the first end of the V-phase winding and the first end of the W-phase winding are respectively connected to the first end of the voltage divider module 20 through corresponding first unidirectional conductive units.
[0035] In one embodiment, the first unidirectional conductive unit includes a first diode, an anode of the first diode is connected to the first end of the corresponding one-phase winding, and a cathode of the first diode is connected to the first end of the voltage divider module 20. Specifically, the three first diodes are first diodes D1, D2, and D3, respectively, an anode of the first diode D1 is connected to the first end of the U-phase winding, an anode of the first diode D2 is connected to the first end of the V-phase winding, an anode of the first diode D3 is connected to the first end of the W-phase winding, and cathodes of the first diodes D1, D2, and D3 are all connected to the first end of the voltage divider module 20.
[0036] In other embodiments, the first unidirectional conductive unit includes a first transistor, the first end of the first transistor is connected to the control end and is connected to the first end of the corresponding one-phase winding, and the second end of the first transistor is connected to the first end of the voltage divider module 20. The first transistor is an N-channel MOS transistor, the first end of the first transistor is the source, the second end of the first transistor is the drain, and the control end of the first transistor is the gate. The anode of the "diode" is formed by connecting the first end of the first transistor to the control end, and the second end of the first transistor is the cathode of the "diode". The first transistor can also be a P-channel MOS transistor. Three first transistors are used instead of the first diodes D1, D2, and D3 to reduce the influence of the diode conduction voltage drop.
[0037] The second unidirectional control unit 12 includes at least three second unidirectional conductive units, and the first end of the U-phase winding, the first end of the V-phase winding and the first end of the W-phase winding are respectively connected to the second end of the voltage divider module 20 through corresponding second unidirectional conductive units.
[0038] In one embodiment, the second unidirectional conductive unit includes a second diode, the anode of the second diode is connected to the second end of the voltage divider module 20, and the cathode of the second diode is connected to the first end of the corresponding one-phase winding. Specifically, the three second diodes are second diodes D4, D5, and D6, respectively, the cathode of the second diode D4 is connected to the first end of the U-phase winding, the cathode of the second diode D5 is connected to the first end of the V-phase winding, the cathode of the second diode D6 is connected to the first end of the W-phase winding, and the anodes of the second diodes D4, D5, and D6 are all connected to the second end of the voltage divider module 20.
[0039] In other embodiments, the second unidirectional conductive unit includes a second transistor, the first end of the second transistor is connected to the control end and is connected to the second end of the voltage divider module 20, and the second end of the second transistor is connected to the first end of the corresponding one-phase winding. The second transistor is an N-channel MOS transistor, the first end of the second transistor is the source, the second end of the second transistor is the drain, and the control end of the second transistor is the gate. The anode of the "diode" is formed by connecting the first end and the control end of the second transistor, and the second end of the second transistor is the cathode of the "diode". The second transistor can also be a P-channel MOS transistor. Three second transistors are used instead of the first diodes D1, D2, and D3 to reduce the influence of the diode conduction voltage drop.
[0040] In one embodiment, the voltage divider module 20 is used to divide the voltage generated between the first end of the voltage divider module 20 and the second end of the voltage divider module 20 to generate a voltage to be measured. The voltage divider module 20 includes a first voltage divider unit and a second voltage divider unit, the first end of the first voltage divider unit and the second end of the second voltage divider unit are connected to the unidirectional control module, and the second end of the first voltage divider unit and the first end of the second voltage divider unit are connected to the detection module 30.
[0041] like Figure 3 As shown, the first voltage-dividing unit includes a first resistor unit R1. The second voltage-dividing unit includes a second resistor unit R2. The first end of the first resistor unit R1 forms the first end of the first voltage-dividing unit and is connected to the cathodes of the first diodes D1, D2, and D3, the second end of the first resistor unit R1 forms the second end of the first voltage-dividing unit, the first end of the second resistor unit R2 forms the first end of the second voltage-dividing unit and is connected to the first end of the first resistor unit R1 to form a virtual center point Zero crossref, the second end of the second resistor unit R2 forms the second end of the second voltage-dividing unit and is connected to the anodes of the second diodes D4, D5, and D6, and finally voltage division is achieved through the first resistor unit R1 and the second resistor unit R2, and a voltage to be measured is generated at the virtual center point Zerocross ref.
[0042] By using 6 common diodes and 2 high-precision resistor units to replace 3 high-precision resistors in the existing solution, the area of the silicon chip and the circuit calibration cost are reduced.
[0043] In one embodiment, the detection module 30 is used to compare the voltage to be measured with the voltage of the first end of another phase winding that does not form a path with the voltage divider module 20 and generate a judgment signal for judging the positions of the U-phase winding, the V-phase winding and the W-phase winding.
[0044] like Figure 3 As shown, the detection module 30 includes a first comparator COMP1, a second comparator COMP2 and a third comparator COMP3, and each comparator corresponds to a phase winding.
[0045] A first end of the first comparator COMP1 is connected to a first end of the U-phase winding, a first end of the second comparator COMP2 is connected to a first end of the V-phase winding, a first end of the third comparator COMP3 is connected to a first end of the W-phase winding, and second ends of the first comparator COMP1, the second comparator COMP2, and the third comparator COMP3 are connected to the voltage divider module 20. Output ends of the first comparator COMP1, the second comparator COMP2, and the third comparator COMP3 output corresponding judgment signals Signal.
[0046] Further, at a certain moment, the first end of the U-phase winding is connected to the positive pole of the power supply through the power switch tube, the first end of the V-phase winding is connected to the negative pole of the power supply through the power switch tube, and the first end of the W-phase winding is suspended. For the U-phase winding, the first diode D1 is forward-biased and turned on, and the second diode D4 is reverse-biased and turned off. For the V-phase winding, the second diode D5 is forward-biased and turned on, and the first diode D2 is reverse-biased and turned off. For the W-phase winding, limited by the motor principle, the induced electromotive force of the W-phase winding is always less than half of the power supply voltage. Since the voltage at the center point O is approximately half of the power supply voltage, the voltage on the W-phase winding is always within the power supply rail range, and the second diode D6 and the first diode D3 are both turned off, so that no current is drawn from the W-phase winding, there is no load effect, and the detection sensitivity is improved.
[0047] The voltage to be measured output by the voltage divider module 20 is the average value of the voltage between the first end of the U phase winding and the first end of the V phase winding, that is, the center point voltage. When the voltage to be measured is compared with the voltage at the first end of the W phase winding, a judgment signal is generated, that is, the W phase winding is crossing the zero point.
[0048] When the three-phase winding rotates, the U-phase winding will be connected to the positive pole of the power supply, suspended, and connected to the negative pole of the power supply in turn, and the voltage at the first end of the U-phase winding will also change continuously, and the same is true for the V-phase winding and the W-phase winding. Therefore, under the action of the three first diodes and the three second diodes, at a certain moment, no matter the first end of the U-phase winding, the first end of the V-phase winding or the first end of the W-phase winding, only the first ends of two of the phase windings form a path with the voltage divider module 20, and the current in the path will generate a voltage to be measured on the voltage divider module 20, and the voltage of the first end of the other phase winding is compared with the voltage to be measured through the corresponding comparator to generate a judgment signal Signal to determine whether the phase winding passes through the zero point.
[0049] In the above example, because the first end of the W-phase winding is suspended, the induced electromotive force of the W-phase winding is always less than half of the power supply voltage, so the judgment signal Signal will be output at the output end of the third comparator COMP3; if the first end of the U-phase winding moves to be suspended, the judgment signal Signal will be output at the output end of the first comparator COMP1; if the first end of the V-phase winding moves to be suspended, the judgment signal Signal will be output at the output end of the second comparator COMP2. It can be set that when the judgment signal Signal jumps from a high level to a low level or from a low level to a high level, it is considered that the corresponding winding has passed the zero point.
[0050] The utility model also discloses a chip, comprising the above-mentioned motor zero-crossing point detection circuit.
[0051] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be regarded as exemplary and non-restrictive from any point of view, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention. Any reference numeral in a claim should not be regarded as limiting the claim to which it relates.
[0052] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.
Claims
1. A motor zero-crossing detection circuit, characterized in that: include: A unidirectional control module, a voltage dividing module and a detection module, wherein the first end of the voltage dividing module and the second end of the voltage dividing module are connected to the first end of the U-phase winding, the first end of the V-phase winding and the first end of the W-phase winding of the motor through the unidirectional control module, and the detection module is connected to the voltage dividing module, the first end of the U-phase winding, the first end of the V-phase winding and the first end of the W-phase winding; The unidirectional control module is used to control the first ends of two phase windings among the first end of the U phase winding, the first end of the V phase winding and the first end of the W phase winding to form a path between the voltage dividing module and the first end of the U phase winding, the first end of the V phase winding and the first end of the W phase winding; The voltage dividing module is used to divide the voltage generated between the first end of the voltage dividing module and the second end of the voltage dividing module to generate a voltage to be measured; The detection module is used to compare the voltage to be measured with the voltage of the first end of another phase winding that does not form a path with the voltage dividing module and generate a judgment signal for judging the position of the winding.
2. The motor zero-crossing detection circuit according to claim 1, characterized in that: The unidirectional control module includes a first unidirectional control unit and a second unidirectional control unit, the first unidirectional control unit is connected to the first end of the voltage divider module and the first end of the U-phase winding, the first end of the V-phase winding and the first end of the W-phase winding, the first unidirectional control unit is used to control the current to flow from the first end of the U-phase winding, the first end of the V-phase winding or the first end of the W-phase winding to the first end of the voltage divider module, the second unidirectional control unit is connected to the second end of the voltage divider module and the first end of the U-phase winding, the first end of the V-phase winding and the first end of the W-phase winding, the first unidirectional control unit is used to control the current to flow from the second end of the voltage divider module to the first end of the U-phase winding, the first end of the V-phase winding or the first end of the W-phase winding.
3. The motor zero-crossing detection circuit according to claim 2, characterized in that: The first unidirectional control unit includes at least three first unidirectional conductive units, and the first end of the U-phase winding, the first end of the V-phase winding and the first end of the W-phase winding are respectively connected to the first end of the voltage divider module through corresponding first unidirectional conductive units.
4. The motor zero-crossing detection circuit according to claim 3, characterized in that: The first unidirectional conductive unit includes a first diode or a first transistor, the anode of the first diode is connected to the first end of the corresponding one-phase winding, the cathode of the first diode is connected to the first end of the voltage divider module, the first end of the first transistor is connected to the control end and to the first end of the corresponding one-phase winding, and the second end of the first transistor is connected to the first end of the voltage divider module.
5. The motor zero-crossing detection circuit according to claim 2, characterized in that: The second unidirectional control unit includes at least three second unidirectional conductive units, and the first end of the U-phase winding, the first end of the V-phase winding and the first end of the W-phase winding are respectively connected to the second end of the voltage divider module through corresponding second unidirectional conductive units.
6. The motor zero-crossing detection circuit according to claim 5, characterized in that: The second unidirectional conductive unit includes a second diode or a second transistor, the anode of the second diode is connected to the second end of the voltage divider module, the cathode of the second diode is connected to the first end of the corresponding one-phase winding, the first end of the second transistor is connected to the control end and to the second end of the voltage divider module, and the second end of the second transistor is connected to the first end of the corresponding one-phase winding.
7. The motor zero-crossing detection circuit according to claim 1, characterized in that: The voltage divider module includes a first voltage divider unit and a second voltage divider unit. The first end of the first voltage divider unit and the second end of the second voltage divider unit are connected to the unidirectional control module. The second end of the first voltage divider unit and the first end of the second voltage divider unit are connected to the detection module.
8. The motor zero-crossing detection circuit according to claim 7, characterized in that: The first voltage dividing unit includes a first resistance unit, and / or the second voltage dividing unit includes a second resistance unit.
9. The motor zero-crossing detection circuit according to claim 1, characterized in that: The detection module includes a first comparator, a second comparator and a third comparator, wherein a first end of the first comparator is connected to a first end of a U-phase winding, a first end of the second comparator is connected to a first end of a V-phase winding, a first end of the third comparator is connected to a first end of a W-phase winding, and a second end of the first comparator, a second end of the second comparator and a second end of the third comparator are connected to a voltage divider module.
10. A chip, characterized in that: It comprises the motor zero-crossing detection circuit as claimed in any one of claims 1 to 9.